Brennan, 77, suffers from memory loss and has been missing from his home on Wheeldon Avenue, Derby, since 4.45pm on Monday.

A statement issued by Derbyshire Police on Thursday afternoon read: "He has friends in the Worksop and Welbeck areas of Nottinghamshire and Derbyshire Police has now widened the search to include these towns."

The statement continued: "Officers are becoming increasingly concerned for his safety as he has memory loss and the weather is poor.

"He is described as white, 5ft 7inches, of slim build, with brown short hair that is going grey.

"He was last seen wearing brown denim trousers with a red cross on the back pocket, a brown cotton-type jacket with a wool lining and a fur collar. He may possibly be wearing a cap. He walks with a stoop.

"Anyone who sees him should call Derbyshire police on 101."

Brennan's training career spans over 40 years, with his best horses including Vulrory's Clown, Speaker Weatherill and Strath Royal, winner of the Charlie Hall Chase at Wetherby in 1998.